In Ref. [1]}, we have shown the results for nine different centrality intervals, from central up to peripheral heavy-ion collision. There accoplanarity distributions for \(\mu ^+\mu ^-\)  production for the kinematics of the ATLAS experiment
[2]}, [3]} were studied. Finally, we have a very nice description of the data including correct normalization and shape of the distributions. At larger acoplanarity, \(\alpha = 1-{|\Delta \phi _{l^+ l^-}| \over \pi }\) , there is a long tail possibly due to soft photon emission [4]}.
